Viscoelastic characteristics of plasticized cellulose nanocomposites

Lee, Dai Hoe; Lee, Jong Hoon; Cho, Mi Sook; Choi, Sung Hun; Lee, Youngkwan; Nam, Jae Do

doi:10.1002/polb.20307

Cited by 15 publications

(11 citation statements)

References 28 publications

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“…However, a clear shift in the β relaxation peak is not always discernible and may even appear to remain invariant or shift slightly upward on the temperature scale [10,73]. For cellulose acetate containing different amounts of diethyl phthalate (DEP) [36,74] the small downward shift of the β transition peak observed at low concentrations did not increase significantly at high DEP concentrations. Similar results were obtained by Seymur et al [75] while the work of Lourdin et al However, a clear shift in the β relaxation peak is not always discernible and may even appear to remain invariant or shift slightly upward on the temperature scale [10,73].…”

Section: Relaxations Interpretation From Mechanical and Dielectric Spmentioning

confidence: 99%

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Antiplasticization of Polymer Materials: Structural Aspects and Effects on Mechanical and Diffusion-Controlled Properties

et al. 2020

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Antiplasticization of glassy polymers, arising from the addition of small amounts of plasticizer, was examined to highlight the developments that have taken place over the last few decades, aiming to fill gaps of knowledge in the large number of disjointed publications. The analysis includes the role of polymer/plasticizer molecular interactions and the conditions leading to the cross-over from antiplasticization to plasticization. This was based on molecular dynamics considerations of thermal transitions and related relaxation spectra, alongside the deviation of free volumes from the additivity rule. Useful insights were gained from an analysis of data on molecular glasses, including the implications of the glass fragility concept. The effects of molecular packing resulting from antiplasticization are also discussed in the context of physical ageing. These include considerations on the effects on mechanical properties and diffusion-controlled behaviour. Some peculiar features of antiplasticization regarding changes in Tg were probed and the effects of water were examined, both as a single component and in combination with other plasticizers to illustrate the role of intermolecular forces. The analysis has also brought to light the shortcomings of existing theories for disregarding the dual cross-over from antiplasticization to plasticization with respect to modulus variation with temperature and for not addressing failure related properties, such as yielding, crazing and fracture toughness.

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Section: Relaxations Interpretation From Mechanical and Dielectric Spmentioning

confidence: 99%

“…[33,55,57,117,144,145] Relaxation spectra: Reduction in glass transition temperature with a depression of β relaxations peak through an increase in relaxation time, resulting in a reduction of the glass formation fragility. [10,36,[73][74][75][76][77][78][79]84,141] Mechanical properties…”

Section: Main Features and Comments Referencesmentioning

confidence: 99%

Antiplasticization of Polymer Materials: Structural Aspects and Effects on Mechanical and Diffusion-Controlled Properties

et al. 2020

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“…This type of directional crystal growth can yield substantial molecular orientation within the transcrystalline layers and thus influence the mechanical properties of the material . Many researchers have reported that polymers with transcrystals were stiff and brittle in comparison with the fine spherulitic polymers; this probably gave rise to a high Young's modulus, adhesion, shear, and tensile yield strengths in the transcrystalline composites . However, previous studies concerning transcrystallized polymer materials have generally focused on fiber composites or model systems.…”

Section: Introductionmentioning

confidence: 99%

Crystallization and mechanical properties of isotactic polypropylene/calcium carbonate nanocomposites with a stratified distribution of calcium carbonate

Wang

Lü

Peng

et al. 2013

J of Applied Polymer Sci

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Isotactic polypropylene (iPP)/calcium carbonate (CaCO3) nanocomposites with a stratified distribution of CaCO3 were prepared by two‐step molding. The iPP and CaCO3 nanoparticles were first mixed by a batch mixer and then compressed into thin layers. Thin iPP/CaCO3 layers alternating with thin neat iPP layers were finally compressed together to form the stratified samples. The transcrystals were observed in the stratified samples by polarized optical microscopy and scanning electron microscopy. The transcrystals grew from the surfaces of the filled layers and occupied most of the space in the neat iPP layers. The β‐form crystals were found in the stratified samples with thick transcrystalline layers, whereas the thickness of the transcrystalline layer was dependent on the content of CaCO3 nanoparticles and the cooling rate of the processing. The relative crystallinity index of the conventional samples first increased and then decreased with the content of CaCO3 nanoparticles. However, the relative crystallinity index of the stratified samples deceased slightly with the content of CaCO3 nanoparticles because of the stratified distribution of the CaCO3 nanoparticles. The stratified samples, except for the samples with high β‐form contents, became more brittle than the conventional samples because of the transcrystal formation in the iPP layers. The stratified samples with high β‐form contents showed much better mechanical properties than the conventional samples. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39632.

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“…According to literature results, chemical modification of fillers can be responsible for reduction of the nucleation abilities as in Refs. or quite the opposite for their increase as in Refs. and .…”

Section: Resultsmentioning

confidence: 80%

Recycling of lignocellulosics filled polypropylene composites. I. Analysis of thermal properties, morphology, and amount of free radicals

Paukszta

Markiewicz

Ostrowski

et al. 2014

J of Applied Polymer Sci

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Composites of isotactic polypropylene filled with comminuted rapeseed straw are studied. Improvement in interfacial adhesion is achieved by chemical modification of the lignocellulose filler. Composites were subjected to recycling by extrusion. The effect of multiple recycling of the composites on the process of nucleation and crystallization of polypropylene matrix, surface topography, and free radical generation was checked. On the basis of differential scanning calorimetry data, a significant influence of the recycling on nucleation activity of the lignocellulose filler was evidenced. A relation between the filler particle size and multiple recycling was established by observations under a polarization microscope, while scanning electron microscope analyses confirmed the positive effect of chemical modification of rapeseed straw on the interfacial adhesion. The composite structure changes forced by multiple recycling are discussed in the context of free radical generation. Concentration of free radicals in the rapeseed straw samples and composites was measured by the electron paramagnetic resonance spectroscopy to show that it was higher in the systems subjected to multiple recycling. Interestingly, the composites after multiple recycling showing elevated concentration of free radicals are also characterized by higher nucleation activity.

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Viscoelastic characteristics of plasticized cellulose nanocomposites

Cited by 15 publications

References 28 publications

Antiplasticization of Polymer Materials: Structural Aspects and Effects on Mechanical and Diffusion-Controlled Properties

Antiplasticization of Polymer Materials: Structural Aspects and Effects on Mechanical and Diffusion-Controlled Properties

Crystallization and mechanical properties of isotactic polypropylene/calcium carbonate nanocomposites with a stratified distribution of calcium carbonate

Recycling of lignocellulosics filled polypropylene composites. I. Analysis of thermal properties, morphology, and amount of free radicals

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